Approximately one million new skin tumors, e.g., non-melanoma and melanoma tumors, are diagnosed each year in the United States. The treatment for most such tumors involves excising the tumor and a region of the skin surrounding the tumor. This so-called peritumoral region may contain tumor cells which have spread locally beyond the observable tumor. In addition to tumor cells, the peritumoral region may also include stroma that has been altered by the cells of the tumor, e.g., by tumor-mediated breakdown of components of the extracellular matrix. To determine the optimal amount of skin to remove, the treating physician typically makes a crude estimate, based upon a visual inspection of the tumor, and removes a corresponding section of the skin.
If the peritumoral region is underestimated, there is the possibility of tumor recurrence from tumor cells lying outside the excised area. Conversely, if the tumor region is overestimated, an unnecessarily large area of skin can be removed, and there is the possibility of unnecessary discomfort and disfigurement to the patient.
For a more precise measurement of the peritumoral region, the treating physician may perform Mohs micrographic surgery (MMS), in which horizontal sections of the region surrounding the excised tumor are examined microscopically for the presence of tumor cells. If tumor cells are detected, then additional skin is removed. MMS can be technically complex and also time consuming because of the time required to process and analyze the samples.